title: Crosstalk between reactive oxygen species and hormonal signalling pathways regulates grain dormancy in barley.
abstract: Seed dormancy, defined as the inability to germinate under favourable conditions, is controlled by abscisic acid (ABA) and gibberellins (GAs). Phytohormone signalling interacts with reactive oxygen species (ROS) signalling regarding diverse aspects of plant physiology and is assumed to be important in dormancy alleviation. Using dormant barley grains that do not germinate at 30 °C in darkness, we analysed ROS content and ROS-processing systems, ABA content and metabolism, GA-responsive genes and genes involved in GA metabolism in response to hydrogen peroxide (H₂O₂) treatment. During after-ripening, the ROS content in the embryo was not affected, while the antioxidant glutathione (GSH) was gradually converted to glutathione disulphide (GSSG). ABA treatment up-regulated catalase activity through transcriptional activation of HvCAT2. Exogenous H₂O₂ partially alleviated dormancy although it was associated with a small increase in embryonic ABA content related to a slight induction of HvNCED transcripts. H₂O₂ treatment did not affect ABA sensitivity but up-regulated the expression of HvExpA11 (GA-induced gene), inhibited the expression of HvGA2ox3 involved in GA catabolism and enhanced the expression of HvGA20ox1 implicated in GA synthesis. In barley, H₂O₂ could be implicated in dormancy alleviation through activation of GA signalling and synthesis rather than repression of ABA signalling.
authors.affiliation: UPMC Univ Paris 06, UR5 - EAC 7180 CNRS, PCMP, Boîte courrier 156, Bat C, 4 place Jussieu, F-75005 Paris, FranceSeed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex, RH17 6TN, UK.
authors.forename: Emilie
authors.initials: E
authors.lastname: Bahin
authors.affiliation: UPMC Univ Paris 06, UR5 - EAC 7180 CNRS, PCMP, Boîte courrier 156, Bat C, 4 place Jussieu, F-75005 Paris, FranceSeed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex, RH17 6TN, UK.
authors.forename: Christophe
authors.initials: C
authors.lastname: Bailly
authors.affiliation: UPMC Univ Paris 06, UR5 - EAC 7180 CNRS, PCMP, Boîte courrier 156, Bat C, 4 place Jussieu, F-75005 Paris, FranceSeed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex, RH17 6TN, UK.
authors.forename: Bruno
authors.initials: B
authors.lastname: Sotta
authors.affiliation: UPMC Univ Paris 06, UR5 - EAC 7180 CNRS, PCMP, Boîte courrier 156, Bat C, 4 place Jussieu, F-75005 Paris, FranceSeed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex, RH17 6TN, UK.
authors.forename: Ilse
authors.initials: I
authors.lastname: Kranner
authors.affiliation: UPMC Univ Paris 06, UR5 - EAC 7180 CNRS, PCMP, Boîte courrier 156, Bat C, 4 place Jussieu, F-75005 Paris, FranceSeed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex, RH17 6TN, UK.
authors.forename: Françoise
authors.initials: F
authors.lastname: Corbineau
authors.affiliation: UPMC Univ Paris 06, UR5 - EAC 7180 CNRS, PCMP, Boîte courrier 156, Bat C, 4 place Jussieu, F-75005 Paris, FranceSeed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex, RH17 6TN, UK.
authors.forename: Juliette
authors.initials: J
authors.lastname: Leymarie
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D018533:Biomass; D003624:Darkness; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005875:Gibberellins / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D001467:Hordeum / Q000187:drug effects / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology; D008954:Models, Biological; D009861:Onium Compounds / Q000494:pharmacology; D057445:Plant Dormancy / Q000187:drug effects; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism* / Q000494:pharmacology; D012639:Seeds / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics
chemical_list: D005875:Gibberellins; D009861:Onium Compounds; D010937:Plant Growth Regulators; D010940:Plant Proteins; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; C007517:diphenyleneiodonium; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; D005978:Glutathione